PROJECT
DESCRIPTION: |
We request support to synthesize sea floor flux
and sediment composition measurements into a global description of biogenic
fluxes in the deep ocean and sediments to provide the basis for testing
models of organic matter fluxes. This work will be comprised of three specific
activities.
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Improve the fundamental data sets and compilations from which the estimated
flux distributions and patterns are derived. This will include the incorporation
of recent results (sedimentary organic C, CaCO3, opal, accumulation
rates, and benthic fluxes of O2, TIC, nutrients, and selected
tracers such as Ba and Ge) into the basic data sets; re-examination of
the methods use to establish the mean sedimentary property fields; and
expansion of the regions considered to include high latitude areas.
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Assimilate the individual measurements into a general Organic C - CaCO3
- Opal diagenetic model to provide a mechanistically more meaningful method
for establishing basin-wide flux patterns.
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Utilize the resulting flux distributions to test current models of particulate
carbon fluxes in the ocean. For example, the importance of diatoms in determining
POC fluxes can be assessed by comparing the ratio of silicate and organic
carbon fluxes in the context of surface water productivity.
The development of an accurate understanding of global biogenic
fluxes will require the synthesis of satellite, process, time-series and
sea floor studies, each providing unique information. Sea floor studies,
while not constraining temporal variability at the same time-scale as surface
water processes, provide an assessment of the spatial distribution of deep
fluxes not attainable by process and time-series studies and not visible
by satellites. Sea floor studies further provide the link between ocean
processes and the sediment record upon which paleoceanographic reconstructions
depend. By providing improved quantitative descriptions of deep water column
fluxes, benthic fluxes and sediment accumulation rates, this project will
contribute to the following SMP objectives:
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Synthesis of observations of particulate export production
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The mechanisms and rates of mid- to deep-water particle flux and remineralizatio
n as well as sediment diagenesis
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Controls on the distributions of the production, transport, and remineralization
of calcium carbonate and silica
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Spatial extrapolation of estimates of biogeochemical fluxes (e.g. export
production) from local to basin and global scales
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